1. Field of the Invention
The air muffler or air muffler and diffuser may be used with air respirators, hood respirators or, as an example, with an air operated cylinder supplied with air by an air compressor. The muffler when used, as an example, with a hood respirator dispenses breathable and clean air to the hood in safe quantities and at acceptable noise levels without endangering the person's life or health.
2. Description of the Prior Art
The Federal Register of Mar. 25, 1972, Volume 37, No. 59, Part II, sets forth the U.S. Government NIOSH/MESA standards for the air supply device required in Supplied Air Respirators, of the Type C class. Such standards require in part that Type C Supplied Air Respirators must each have a minimum of 4 CFM of air at a stated (PSI) pressure and a noise level of 80 dBA or less delivered into the enclosed snug fitting hood respirators with a predetermined length of hose from the air source.
Various mufflers have been used heretofore with little success. In the past cotton filters and paper base fiber filters have been used in casings delivering air from the source to the hoods. Such materials absorbed moisture and the materials became packed in the end of the tubes or casings as a result of the air pressure against the diffusing fibers. This resulted in the ports of the casing becoming clogged and the filtering materials losing their air diffusing characteristics. Thus such devices after continued use do not normally meet the national standards and present a health problem since dusts, mists, fumes and other non-toxic particles are not filtered from the air supplied by the compressor. Unacceptable noise levels also result.